The hacker activist group Anonymous is calling for people online to "troll" Islamic State on December 11 as part of its self-declared war on the extremist militant group.

In a posting on Ghostbin, Anonymous called for people to “show your support and help against ISIS by joining us and trolling them” as part of “a day they never forget.”

The group called for people to take to social media sites like Facebook, Twitter and YouTube to mock IS and to call them “daesh” a derogatory Arabic acronym for the group. The group said it wants to get the hashtags #daesh and #daeshbags trending on Twitter.

Anonymous also called for people to find pictures of dead militants to distribute both virtually and in real life.

The collective of hackers also urged people to find IS accounts on social media and to report them for possible deletion.

“They [IS] thrive off of fear they hope that by their actions they can silence all of us and get us to just lay low and hide in fear,” according to the Anonymous post. “But what many forget and even they do is that there are many more people in the world against them than for them. And that is the goal of this mass uprising, on December 11th we will show them that we are not afraid,we will not just hide.”

'Attacks cannot remain unpunished'

In addition to virtual trolling, Anonymous will have rallies in several U.S. and Canadian cities.

Anonymous declared its war against IS in the wake of the November terrorist attacks in Paris.

"These attacks cannot remain unpunished," said a masked figure in a video released by the group.

The hacker group rose to prominence after a series of cyber attacks against individuals, governments and organizations that it does not approve of, including PayPal, Mastercard and the Church of Scientology, among others.

The group says it has identified more than 39,000 suspected IS profiles and reported them to Twitter. It claims to have had more than 25,000 of these accounts suspended. Nearly 14,000 more on the targeted list remain active, according to a list posted to a site calling itself Lucky Troll Club.

The “Islamic Cyber Army," the Islamic State’s cyber arm, responded to Anonymous’ declaration of “total war” by calling the shadowy hacking group “idiots.”